Definition of Ventilation – This book covers the entire syllabus of “Community Health Nursing” prescribed by the Universities of Bangladesh- for Basic and diploma nursing students. We tried to accommodate latest information and topics.
This book is examination friendly setup according to the teachers’ lectures and examination’s questions. At the end of the book previous university questions are given. We hope in touch with the book students’ knowledge will be upgraded and flourished. The unique way of presentation may make your reading of the book a pleasurable experience.
Definition of Ventilation
Definition of ventilation
Ventilation is the science maintaining atmospheric conditions which are comfortable and healthful to the human body.
Classification of ventilation
1. Natural ventilation:
2. Wind: –
- Perflation: When wind blows through a room it is called perflation.
- Aspiration: When there is an obstruction wind by pass and exerts a suction action at its tail end – this is called aspiration.
- Gross ventilation: Doors and windows facing each other provide cross ventilation.
1. Diffusion:- Air passes through the smallest opening or spaces by diffusion.
2. Inequality of temperature:
- Air flows from high density to low density.
- Density of air depends on temperation of air.
A. Mechanical or artificial ventilation:
a.Exhaust ventilation: It is negative pressure ventilation in which air is exhausted from a a room by exhaust fans they lie for apertures of external well,
1. Plenum ventilation;
- It is positive pressure ventilation on which air is blown into a room by centrifugal fans.
2. Balanced ventilation:
- It is combination of positive and negative ventilation.
3. Air conditioning:
- It is defined as the process of treating air so as to control simultaneously its temperature, humidity, cleanliness and air movement to meet the requirements of the conditioned space.
Or (another answer)
Types of ventilation
1. Mechanical ventilation refers to any system that uses mechanical means, such as a fan, to introduce subaerial air to a space. This includes positive pressure ventilation, exhaust ventilation, and balanced systems that use both supply and exhaust ventilation.
2. Natural ventilation refers to intentionally designed passive methods of introducing subaerial to a space without the use of mechanical systems.
3. Mixed mode ventilation (or hybrid ventilation) systems use both natural and mechanical processes.
4. Infiltration is the uncontrolled flow of air from outdoors to indoors through leaks (unplanned openings) in a building envelope. When a building design relies on environmentally driven circumstantial infiltration to maintain indoor air quality, this flow has been referred to as adventitious ventilation
Purposes of ventilation
i. Replacement of vitiated air by a supply of oxygen and fresh air.
ii. Controlling of the purity of incoming air with regard to its temperature, humidity and purity in order to provide thermal environment.
iii. Diluting of air-borne contaminations to an acceptable concentration.
Criteria of good ventilation
1. It. should prevent chilling and drying of the body as well as stagnation of the body heat.
2. It should be able to remove gases, odors, bacteria, dust etc. which contaminate the air, dilute it and remove the impurities produced inside the room through vitiating process
Ill ventilation:
Ill ventilation means to drive foul air out of an enclosed area that is, no beneficial for health and/or respiratory function.
Effects of ill-ventilation in a room
1. In vitiated air the following physical changes are noticed:
2.A rise in temperature
3. Increased humidity
4. Stillness
5. The above changes produce the following ill conditions:
6. Headache
7. Inability to concentrate
8. Drowsiness
9. Lassitude
10. Depression of spirits
11. Loss of appetite
12. A tendency to catch cold easily, and
13. Diminished resistance to infectious diseases, (e.g. rickets in children and pulmonary tuberculosis are specially related to insufficient ventilation).
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